Philosophical Topics

Neutral Theory is controversial in ecology. Ecologists and philosophers have diagnosed the source of the controversy as: its false assumption that individuals in different species within the same trophic level are ecologically equivalent, its conflict with Competition Theory and the adaptation of species, its role as a null hypothesis, and as a Lakatosian research programme. In this paper, I show why we should instead understand the conflict at the level of research programs which involve more than theory. The Neutralist and Competitionist research programs borrow and construct theories, models, and experiments for various aims and given their home ecological systems. I present a holistic and pragmatic view of the controversy that foregrounds the interrelation between many kinds of practices and decisions in ecological research.

The concept of population is central to ecology, yet it has received little attention from philosophers of ecology. Furthermore, the work that has been done often recycles ideas that have been developed for evolutionary biology. We argue that ecological populations and evolutionary populations, though intimately related, are distinct, and that the distinction matters to practicing ecologists. We offer a definition of ecological population in terms of demographic independence, where changes in abundance are a function of birth and death processes alone. However, demographic independence (DI) is insufficient on its own so we supplement it with the idea of shared habitat. An ecological population is a group of organisms of the same species in a habitat that manifests DI. Given the importance of metapopulation dynamics to modern ecology, an account of ecological population must apply to this domain as well. Thus, we extend our definition of ecological population to the metapopulation. To facilitate the extension, we introduce the metahabitat—a collection of spatially segregated habitat patches shared by a single DI population. This enables us to (1) diagnose some unhelpful trends in the metapopulation literature and (2) emphasize the importance of habitat dynamics in pursuit of the goals of theoretical ecology and conservation biology.

Researchers studying linked Social-Ecological Systems (SESs) often use the notion of coevolution in describing the relation between humans and the rest of nature. However, most descriptions of the concept of socio-ecological coevolution remain elusive and poorly articulated. The objective of the following paper is to further specify and enrich the meaning of “coevolution” in social-ecological studies. After a critical analysis of two accounts of coevolution in ecological economics, the paper uses the frameworks of Niche Construction Theory and the Geographic Mosaic Theory to define social-ecological coevolution as the reciprocal adaptation of human-social and ecological ensembles through human and ecological niche construction activities. In sum, this conceptual analysis suggests that an ecologization of Darwinian coevolution can bring clarity to profound functional integration that takes place between humans and ecological systems, and at the same time opens fruitful avenues for social-ecological research.

Prediction is an important aspect of scientific practice, because it helps us to confirm theories and effectively intervene on the systems we are investigating. In ecology, prediction is a controversial topic: even though the number of papers focusing on prediction is constantly increasing, many ecologists believe that the quality of ecological predictions is unacceptably low, in the sense that they are not sufficiently accurate sufficiently often. Moreover, ecologists disagree on how predictions can be improved. On one side are the ‘theory-driven’ ecologists, those who believe that ecology lacks a sufficiently strong theoretical framework. For them, more general theories will yield more accurate predictions. On the other are the ‘applied’ ecologists, whose research is focused on effective interventions on ecological systems. For them, deeper knowledge of the system in question is more important than background theory. The aim of this paper is to provide a philosophical examination of both sides of the debate: as there are strengths and weaknesses in both approaches to prediction, a pluralistic approach is best for the future of predictive ecology.

The variety of nature presents a challenge for ecologists. Individual organisms differ from one another in ways both obvious and subtle, even if they’re members of the same species living in the same location. Different populations, species, communities, ecosystems, biomes, habitats, food webs, etc. also differ from another. What, if anything, can be said in general about ecological systems and how they work? If there are generalities in ecology, do they take the form of exceptionless “laws of nature” analogous to the laws of physics? Or do they take some other form? Should ecologists even try to identify ecological generalities? If so, how? The variety of nature is matched by the variety of ecologists’ answers to those questions. I will suggest that all of their answers are right—sometimes. Here I propose a taxonomy of the many different “roads to generality” in ecology: the various different kinds of “generality” that ecologists seek. I argue that each road to generality is valuable in its own way, but that different roads are useful in different contexts and for different purposes. Different roads to generality thus can be complementary to one another, and it would be a mistake for the field of ecology as a whole to focus exclusively on any one of them.

Perhaps no concept has been thought more important to ecological theorizing than the niche. Without it, technically sophisticated and well-regarded accounts of character displacement, ecological equivalence, limiting similarity, and others would seemingly never have been developed. The niche is also widely considered the centerpiece of the best candidate for a distinctively ecological law, the competitive exclusion principle. But the incongruous array and imprecise character of proposed definitions of the concept square poorly with its apparent scientific centrality. I argue this definitional diversity and imprecision reflects a problematic conceptual indeterminacy that challenges its putative indispensability in ecology.

The question of whether there are laws of nature in ecology has developed substantially in the last 20 years. Many have attempted to rehabilitate ecology’s lawlike status through establishing that ecology possesses laws that robustly appear across many different ecological systems. I argue that there is still something missing, which explains why so many have been skeptical of ecology’s lawlike status. Community ecology has struggled to establish what I call a General Unificatory Theory (GUT). The lack of a GUT causes problems for explanation as there are no guidelines for how to integrate the lower-level mathematical and causal models into a larger theory of how ecological assemblages are formed. I turn to a promising modern attempt to provide a unified higher-level explanation in ecology, presented by ecologist Mark Vellend, and advocate for philosophical engagement with its prospects for aiding ecological explanation.

Recent examples of rapid evolution under natural selection seem to require that the disciplines of ecology and evolution become better integrated. This inference makes sense only if one’s understanding of these disciplines is based on Hutchinson’s two-speed model of the ecological theater and the evolutionary play. Instead, these disciplines are more accurately viewed as occupying distinct “epistemic niches.” When so understood, we see that rapid evolution under selection, even if it is generally true, does not imply that evolutionary explanations are improved by the inclusion of ecological details. Nor are ecological explanations necessarily improved by the inclusion of information about trait variation, heritability, effective population size, or other standard evolutionary factors. To illustrate, I develop a version of Kitcher’s (1984) “gory details” argument to show that, even for some trait that is under strong directional selection, a dynamically sufficient explanation of its ecological relationships should ignore most of the information explaining why that trait is evolving. The wholesale integration of ecology and evolution looks even less appealing when empirical sufficiency, a purely practical requirement, is taken into account. As a way forward, I propose an eco-evo partitioning framework. This strategy enables researchers to estimate the empirical sufficiency of a purely ecological, a purely evolutionary, or a combined eco-evo approach.

In this essay, I argue that the selected effects approach to ecosystem functions is inadequate and defend the adequacy of the systemic capacity account. I additionally argue that rival persistence enhancing and organizational approaches face serious problems when applied to ecosystem ecology. Lastly, I explore how the systemic capacity approach applies to recent experimental work on biodiversity and ecosystem functioning.

Sagoff (2017) critiqued the exclusion of cultivated plants and animals from much of the body of work in ecology. However, there is a history of attempting to incorporate cultivated landscapes in ecology that goes back at least two decades, particularly in urban ecology. The subdiscipline of urban ecology has received relatively little attention in philosophy, although some of its methodologies, such as coupled human-natural systems research, have been critiqued. Here I will attempt to explicitly address the conceptual limitations in ecology for studying cultivated ecosystems and evaluate these limitations in the context of coupled human-natural systems and socioecological research, urban ecosystem services frameworks, and actor-network theory. I argue that the history of cultivated organisms is highly germane to their ecology, necessitating the incorporation of human agency into ecological theory. However, human agency and nonhuman nature exist along a continuum of nature vs. culture. As a result, dualistic approaches to studying the role of human agency in ecosystem processes, such as socioecology and ecosystem services assessments—which explicitly separate humans from nature—have had limited success in cultivated landscapes. More fully integrated frameworks such as actor-network theory may better address ecological research questions in cultivated landscapes.

Fundamental terms in the field of ecology are ambiguous, with multiple meanings associated with them. While this could lead to confusion, discord, or even tests that violate core assumptions of a given theory or model, this ambiguity could also be a feature that allows for new knowledge creation through the interconnected nature of concepts. We approached this debate from a quantitative perspective, and investigated the cost of ambiguity related to definitions of ecological units in ecology related to the general term “community.” We did a meta-analysis of tests associated with two bodies of literature, Hubbell’s unified neutral theory of biodiversity and biogeography and Diamond’s assembly rules, that rely on a specific ecological unit that assumes that species are existing within a local area and that they have overlapping resource needs. We predicted that if ambiguous terminology is widespread, then researchers will have tested them with many different ecological units, that in addition some of these ecological units will violate the core assumptions of the theory, and finally that the overall level of support for a theory will be stronger if appropriate ecological units were used. We found that indeed multiple different ecological units were used in the literature to test both theories, with 65 percent appropriate ecological units for neutral theory tests, and only 6 percent for assembly rule tests. Finally, there was some evidence that the support for a theory depended on whether appropriate ecological units were used for neutral tests, but there was not enough data for the assembly rule tests. These results thus show that ambiguous terminology in ecology is having measurable effects on research and is not of solely philosophical concern. We advocate that authors be explicit in their writing and outline core assumptions of theories, that researchers apply these consistently in their tests, and that readers be attentive to what is written and cognizant of their potential biases.

Values have a profound influence on the behaviour of all people, scientists included. Biodiversity is studied by ecologists, like myself, most of whom align with the “mission-driven” field of conservation biology. The mission involves the protection of biodiversity, and a set of contextual values including the beliefs that biological diversity and ecological complexity are good and have intrinsic value. This raises concerns that the scientific process might be influenced by biases toward outcomes that are aligned with these values. Retrospectively, I have identified such biases in my own work, resulting from an implicit assumption that organisms that are not dependent on natural habitats (e.g., forests) effectively do not count in biodiversity surveys. Finding that anthropogenic forest disturbance reduces the diversity of plant species dependent on shady forests can thus be falsely equated with more general biodiversity loss. Disturbance might actually increase overall plant diversity (i.e., including all of the species found growing in a particular place). In this paper I ask whether ecologists share values that are unrepresentative of broader society, I discuss examples of potential value-driven biases in biodiversity science, and I present some hypotheses from behavioral economics on possible psychological underpinnings of shared values and preferences among ecologists.